North Korean state media on Sunday reported that Russian President Vladimir Putin had expressed his willingness to visit Pyongyang when he met with North Korean Foreign Minister Choe Son Hui in Russia earlier in the week.

Putin also thanked North Korean leader Kim Jong Un for the invitation, state news agency KCNA said, citing the Foreign Ministry.

No date has been set for a potential visit but KCNA cited Pyongyang's Foreign Ministry as saying it would come at an "early date."

It would be the Russian leader's first trip to North Korea in more than two decades. Putin visited Pyongyang in July 2000 for a meeting with Kim Jong Il, the father of Kim Jong Un.

Russia has also said a trip in the works

Kim visited Russia for several days last year. North Korea's Foreign Minister Choe Son Hui returned from Moscow on Friday. 

KCNA also reported on Sunday that Pyongyang had agreed to further strategic and tactical cooperation with Russia.  It cited the Foreign Ministry as saying Russia had expressed "deep thanks" to North Korea for its "full support" in Ukraine. 

Kremlin spokesman Dmitry Peskov had said earlier in the week that Moscow hoped a visit would pan out. Peskov said Putin would travel to North Korea "in the forseeable future." 

Kim traveled to Russia last year in September in a trip that focused heavily on military cooperation between the two, even though both countries are under a raft of sanctions.

US warnings of increased cooperation

Washington and allies have repeatedly raised concerns about weapons deals from Pyongyang to supply Russia's war in Ukraine.

On Thursday this week, the White House's senior director for arms control Pranay Vaddi warned that the the nature of the threat posed by North Korea could change "drastically" in the coming decade if it continues seeking closer ties with Russia. 

"What we're seeing between Russia and North Korea is an unprecedented level of cooperation in the military sphere," Vaddi told Washington's Center for Strategic and International Studies think tank.

US intelligence officials earlier this month said that Russia had acquired ballistic missiles from North Korea and was seeking close-range ballistic missiles from Iran.

UN Security Council resolutions, approved with Russian support, ban countries from trading weapons or other military equipment with North Korea.

rm/msh (Reuters, AP)